FANUC Series 16/18/160/180-Model C Machining Center Operators Manual

PROGRAMMING
B–62764EN/01
16. CUSTOM MACRO
405
For smooth machining, the CNC prereads the NC statement to be
performed next. This operation is referred to as buffering. In cutter
compensation mode (G41, G42), the NC prereads NC statements two or
three blocks ahead to find intersections. Macro statements for arithmetic
expressions and conditional branches are processed as soon as they are
read into the buffer. Blocks containing M00, M01, M02, or M30, blocks
containing M codes for which buffering is suppressed by setting
parameters No.3411 to No.3420, and blocks containing G31 are not
preread.
N1 G31 X100.0 ;
N2 #100=1
:
>
> :Block being executed
NC statement
execution
Macro statement execution
Buffer
N1
N2
N1 X100.0 ;
>
> : Block being executed
j : Block read into the buffer
NC statement
execution
Macro statement
execution
Buffer
N1
N2
N3
N4
N2 #1=100 ;
N3 #2=200 ;
N4 Y200.0 ;
:
N4
When N1 is being executed, the next NC statement (N4) is read into the
buffer. The macro statements (N2, N3) between N1 and N4 are processed
during execution of N1.
16.7
PROCESSING
MACRO
STATEMENTS
Explanations
D When the next block is
not buffered
(M codes that are not
buffered, G31, etc.)
D Buffering the next block
in other than cutter
compensation mode
(G41, G42) (normally
prereading one block)

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